The work concerns uveoretinal inflammatory disease mechanisms. The study focused on evaluating the role of resident cells at the target organ level. Muller cells interactions with T-lymphocyte cell line was studied in vitro. Two opposite effects of Muller cells on T-lymphocytes proliferation were found that could be expressed under different culture conditions. An inhibitory effect on antigen driven poliferation of T-helper lymphocytes could be modulated with various drugs that allowed the Muller cells to function as antigen presenting cells.